A plurality of manufacturing processes for producing hollow plastic bodies is known from the prior art. In the simplest case, two separate halves of a hollow plastic body, such as of a fuel tank for a motor vehicle, are formed from a thermoplastic synthetic material, for example by compression molding, which are then, for example, thermally welded together in a subsequent process step. This manufacturing process is comparatively laborious because the individual steps cannot be carried out in a machine. Moreover, the stress-resistance of the produced weld is rather low.
Higher-quality hollow plastic bodies that have a high mechanical stress-resistance, e.g. in relation to a super-atmospheric internal pressure, may be produced by means of the so-called blow molding extrusion technique. For this purpose, a tube is extruded from a thermoplastic synthetic material, which is expanded by means of air blown in and fed to the cavity of a heated molding tool. Seamless hollow bodies with a more complex shape can in that case also be molded in the cavity. Seams that weaken the structure can be minimized in this way. Modern blow molding methods even permit varying wall thickness in the hollow body produced. Blow molding methods can be used, for example, for producing bottles, canisters, barrels, tanks, pipes and tubes. But hollow bodies with a more complex shape, such as highly tight fuel tanks, structural parts or engine compartment enclosures for motor vehicles, and even transport pallets can be produced by means of the blow molding technique. One draw-back of the blow molding technique is the comparatively high machine expenditure, which prohibits employing this technique for small quantities. In addition, combinations of different materials, for example with different chemical or physical properties, are not possible.